Houston’s annual HIV infection rate is nearly twice the national average, according to figures released on World AIDS Day, December 1, by the city’s health department, the Houston Chronicle reports.

The data are based on a more accurate calculation method used by the U.S. Centers for Disease Control and Prevention (CDC), which announced in early August that the country’s rate of HIV incidence was 40 percent higher than previously estimated.

Nationwide, there are 23 new infections for every 100,000 people, compared with 44 per 100,000 in Harris County, where Houston is located. In 2006, about 1,700 of the county’s residents became HIV positive.

“In one year, one in 2,000 Houstonians becomes infected with HIV,” said Tom Giordano, MD, medical director at the Harris County Hospital District’s Thomas Street Health Center. “That’s a pretty alarming statistic.”

According to the article, although blacks and Latinos account for only 60 percent of Houston’s population, they made up 78 percent of the city’s HIV cases in 2006. Houston’s health department is using prevention efforts in both communities and is assigning mobile testing vans to areas in the city with the highest HIV rates.